ANF levels and response to captopril have been found autosomal dominant polycystic disease to be exaggerated in the hypertensive ADPKD population. In order to determine the role of cardiac preload and venous tone, we are investigating 20 ADPKD subjects on high sodium diets- 300mEQ/day and measuring venous response to exercise, nitroglycermine and ANF levels with cardiac catheterization.